DE3712354A1 - ROTARY PISTON BLOWER - Google Patents

Description

The invention relates to a rotary piston blower with each other at relative speed non-contact, a gap between them sealing work or shut-off parts and Workspace walls.

There is almost one of such machines in itself vast amount of types and variations of these Types, but only a very limited number has attained practical importance and has been preserved. These are off-axis machines like the roots like, the half and quarter roll blower and in Nine-axis, meshed machines like this like screw compressors. All have in common that them between the workspace walls and the ar parts or shut-off parts (rotor, piston or screw ben) changing, d. H. shifting or increasing and decreasing in volume Include rooms. A contactless start of the work space forming parts is required to Loss of friction when starting immediately  avoid and around the work area and thus the ge to be able to keep subsidized work equipment oil-free.

In mass production, the ar with machine room forming machine parts reach a few tenths of a millimeter. With a load layering with a plastic with good sliding properties as described in DE-OS 36 21 178.8 much better results can be achieved len because such a coating itself up Column of a few hundredths of a millimeter in operation can grind in. However, you can only under major manufacturing difficulties on the Apply piston blanks accurately and requires one considerable processing by turning or the like chen, but most of all has the disadvantage that it is under the influence of operating heat, the 120 ° C and can achieve more, due to centrifugal force.

It is also known that the drive part a coating of coal from rotary piston exhaust gas loaders on the walls of the workspace, which forms on the running surfaces of the work space forming parts retracts even in the narrowest gap during operation. However, this is only possible with exhaust machines and it is not a constructive measure on the Ma Rail parts themselves, but only one on the coal process that acts in a natural way, the result of which is random and uncertain.

The object of the invention was an execution of the work space forming parts of the machines mentioned at the beginning, in the largest possible Precision without increased design and costs effort, especially without subsequent revision after formation, the formation of the tightest sealing Gaps between each other and also higher loading withstands operating temperatures.

The solution to this problem arises in the beginning mentioned rotary piston blowers from the in the An measures and arrangements specified.

The coated with the foamed plastic or parts consisting of it run on the Ge the narrowest possible gap. It is it expedient that one each from foamed Plastic existing surface or edge on a Ge metal surface or edge, whereby the Metal surface should be so rough that the foam counter surface is abraded when touched. This roughness, which is about 100 to 150 microns should be good with sandblasting but also with Make etches through which the crystallite structure structure of the metal is exposed. It is therefore too avoid, as well as not metal against metal should run, foam surfaces with foam to pair surfaces. This roughening of the metalli surfaces that resemble files on his Surface acts on compressed plastic necessary because smooth metal surfaces in the immediate Tarnishing the foam act as a brake and the  according to no grinding of the foam parts can take place. As far as the machine type is concerned leaves, the foam surface is on the part assign to which a lower centrifugal force acts as the part with the counter surface to the Centrifugal force anchoring the foam reduce fabric parts.

The binding of the foam parts to the ones carrying them Metal structures can also be created by creating a Roughness of those to be connected to the foam Metal surfaces very much by the resulting Enlargement of the binding area can be improved. This can be done by sandblasting or by etching happen.

In larger foam parts are expedient Provide cavities to allow internal thermal expansion to allow for changes in gap width by keeping operating temperatures as low as possible. These cavities can be seen when foaming Produce axially inserted mold cores.

The manufactured in the manner according to the invention Machine parts have essentially the same ge important as the usual hollow trained Extruded aluminum profiles. It therefore needs to their balancing no special arrangements.

The foam parts are manufactured in External tools that comply with appropriate shrinkage or growth of the foam the correct form of the tolerances, the negative form of the  represent part to be preserved, by foaming. In these tools are the metal parts on which the foam should be tied up before use roughening and any hollow spaces in the foam-producing mold cores that after Molds are pulled out. The foam is preferably polyurethane foamed with water. Foaming with fluorocarbons is to avoid because of the foam during operation heat emitted fluorine-containing gas the metal parts the machine corrodes. With water-foamed poly Urethane also occur at operating temperatures no thermal expansion caused by blowing agent.

After all, it is useful to have the tools for that Foaming to heat, because then on the work adjacent surfaces a compression of the foam material that grinds in during operation favored.

The machine parts according to the invention can be there they mostly rotating bodies with axially parallel cylin The surfaces are made of roughened in the above foamed extruded aluminum produce parts without much rework. The one driving or grinding in only requires a short run times of the machine, the processed material of the foam accumulates as harmless dust and is blown out of the machine.

The blowers according to the invention are therefore very suitable good for cheap mass production. They point as a result  their very extensive tightness performance, that have not been previously provided by such fans could.

Embodiments of fan according to the invention common types are described below using the Described drawings. Show it

Figure 1 is a radial section through a piston of the half-roll construction according to the Invention in the plane II in Fig. 2.

Figure 2 shows an axial section through a fan according to the invention of the half-roll design in plane III-III in Fig. 1.

Fig. 3 is a radial section through a fiction, gemaßen pistons of quarter-roller construction;

Figure 4 shows another embodiment of a piston according to the Invention of a half-roll fan in radial section.

FIG. 5 shows another embodiment of a piston according to a quarter of a rolling fan in radial section Inventions;

Figure 6 is a radial section through a fiction, according Roots blower.

Figure 7 is a radial section through a rotary piston fan according to the Invention in meshing.

Fig. 8 is a perspective view of a screw compressor according to the invention;

Figure 9 is a radial section through a fiction, modern scroll compressors.

Fig. 10 is a partial axial section of the scroll compressor of FIG. 9.

The piston of the half-roll construction shown in FIG. 1 has a wing 1 with a cylindrical surface 2 with a large radius and a cylindrical surface 3 with a small radius. The cylinder surface 2 with a large radius extends over 135 °, the cylinder surface 3 with a small radius over 180 °, measured with the cylinder axis as the center. Between the two cylinder surfaces 2 and 3 symmetrical engagement surfaces 4 and 5 are provided, which are each bent at an angle of 120 ° to a convex curve 6 and 7 from the outside and each of an outer flat engagement surface 8 and a flat inner engagement area 9 exist. The inner engagement surfaces 9 go into concave curves 10 and 11 in the cylinder surface 3 with a small radius. The outer flat engagement surfaces 8 cut the cylinder surface 2 at an obtuse angle of 120 °. The inner grip surfaces 9 are therefore in the parting plane 12 between the wing 1 and the cylindrical surface 3 with the small radius.

The wing 1 consists essentially of the plastic body 13 made of foamed polyurethane, which forms a solid non-porous wall on its outer walls, since its formation takes place by foaming in closed tool and therefore the plastic foam after the walls of the tool up to extensive Pore freedom compressed due to its internal pressure. The force introduction of drive pins 14 into this plastic body 13 takes place through a section of an extruded light metal profile 15 foamed into the plastic body 13 .

The cylinder surface 3 with a small radius forming piston part 16 is part of the extruded Leichtme tallprofiles 15 and is filled with lead as a counterweight 17 to the wing 1 . In the axial flanks of the light metal profile 15 , the shaft journals 18 on the left in FIG. 2 and 19 on the right are inserted, which have disks 22 , 23 running in turns of the housing side walls 20 , 21 . With the washers 22 , 23 , the stub shafts at 24 are screwed to the light metal profile 15 .

The plastic body 13 is anchored in the light metal profile 15 in its ribs 26 , 27 , 28 , 29 , 30 . These ribs 26 , 27 , 28 , 29 , 30 are shown in different embodiments in FIG. 1. They can have lateral anchoring ribs 31 , 32 , 33 and openings 34 in these ribs. As a result, who formed the sufficient undercuts in which the rigid and solid plastic body 13 is held securely against the centrifugal forces generated during operation. The ribs 26 , 27 , 28 , 29 , 30 , like the anchoring ribs 31, 32, 33, run axially and can be pulled out without difficulty when extruding the light metal profile 15 . When it foams, the plastic enters all cavities and undercuts of the light metal profile, so that a homogeneous piston is formed during curing, which can absorb and transmit all forces occurring during operation.

In the embodiment shown in FIG. 1, the outer ribs 26 and 30 are also part of the outer engaging surface 8 . Likewise, the inner engagement surface 9 is formed by the Leichtmetallpro fil 15 . These two engagement surfaces 8 and 9 have no sealing function and can therefore be disregarded. The sealing during the transition from the rolling of the two-sided cylinder surfaces 2 and 3 take over the contact-free starting convex curves 6 and 7 between the engagement surfaces 8 and 9, the sealing of the leak path between the two pistons. Of these Rundun conditions, the right rounding 7 of the piston shown in FIG. 2 is made of the same foam as that of the foam body 13 when it is foamed by passing through the opening 35 in the light metal profiles 15 . In contrast, the left curve 6 of this piston consists of metal. In the opposite piston, the left rounding 6 is reversed corresponding to the rounding 7 of the piston shown in Fig. 3 made of foam while the right rounding 7 of the counter-piston consists of Me tall. There is therefore always a rounding of foam on a rounding of aluminum of the counter-piston.

The surface of the jacket raceways 36 and 37 of the housing ( Fig. 3), the cylindrical surfaces with the small radius, the metallic curve 6 of the piston and the metallic curve 7 of the counter-piston are roughened by sandblasting, so that there is always a foam surface with a roughened aluminum surface is paired and can grind on it, but never foam with foam and just as little metal with metal. This means that metal meets foam on all sealing surfaces that come together.

Since the light metal profile 15 must also be roughened by sandblasting on the surfaces on which the foam body, including the curves 6 and 7 , in order to enlarge the bonding area, the light metal profile 15 can be sandblasted on all sides in one operation. The same is possible with etching by dipping the light metal profile 15 .

The housing seal with respect to the shaft passages in the side walls 20 , 21 takes place by means of disks 22 , 23 which are arranged concentrically around the shaft journals 18 , 19 . According to previous technology, the seal existed in the narrowest gap spaces between the circumferential surfaces of these disks 22 , 23 and their extensions in the housing side walls 20 , 21 , because these gap spaces could be produced more easily by turning out than the gaps lying in the radial plane between the bottom of these recesses and the disks 22 , 23 . The task of this seal is not only the prevention of leakage of the compressed gas but the penetration of bearing grease and lubricating oil into the working rooms at low pressure in these compared to the storage and transmission rooms. Oil penetration results in undesirable oil contents in the production gas. Withdrawing the bearing grease causes the bearings to run dry. The gap seals on the circumference of the disks 22 , 23 , that is to say that of metal against metal, only allow gaps of tenths of a millimeter. According to the invention, concentrically circumferential recesses 36 are provided in the disks 22 , 23 , which, like the wings 1 of the pistons, are foamed with plastic in a die-casting process. These recesses 36 are of different depths so that the disks 22 , 23 can act as counterweights. On the side of the flights 1 , the recesses 37 forming a semicircular ring are axially deeper than the recesses 38 forming the other semicircular ring on the side of the piston part 16 with a small radius. The difference results from the necessary mass of the counterweights, which can be adjusted in this way. The counter-contact surfaces 39 of these foams and the edges of the shaft bearing rings 40 are roughened like the aforementioned metallic contact surfaces, so that there is a grinding of this shaft passage seal on hundredths of a millimeter. This arrangement therefore saves in most cases further measures to prevent lubricants from entering the workrooms.

The piston of the quarter construction shown in FIG. 3 is radially symmetrical and therefore does not require any balancing of its two wings 41 and 42 . These consist in the same way as the wing 1 from the two foam bodies 43 and an anchored in this by foaming in the die-casting process with ribs 44 , 45 , 46 , 47 , 48 , 49 50 Filen. This light metal profile 50 is here the carrier of the two foam bodies 43 and transmits the force of the shaft 51 arranged in it to them. The ribs 44 , 45 , 46 , 47 , 48 , 49 which are continuous in the axial direction have anchors 52 which, like the ribs themselves, can have different shapes, examples of which are shown in FIG. 1. Openings 53 are provided in these ribs, which have the same function as the openings 34 and FIG. 1.

The between the cylindrical surfaces 54 with a large radius and the cylindrical surfaces 55 with a small radius before seen engagement surfaces 56 and 57 and the roundings 58 and 59 lying between these have the same surface geometry as those of the half-roller wing shown in FIG. 1. According to the requirement that foam surfaces should always start on roughened metal surfaces, the cylinder surfaces 54 are formed with a large radius of foam, but the cylinder surfaces 55 with a small radius are made of roughened metal. Likewise, the convex rounded portion 56 is made of roughened metal in both piston wings while the rounded portions 57 on the other side of the piston wing are made of foam. The connection of the latter with the foam bodies 43 is the same as that shown in Fig. 1 th piston of a half-roll machine. The manufacturing process of such pistons is the same as there. In the case of the opposed pistons, these convex roundings would have to be a mirror image of foam or metal, so that a rounding of foam material runs up against such a metal and can grind in on it.

Finally, it is expedient to also roughen the Mantellaufbah NEN 58 and 59 of the housing and the housing Seitenwän de 20 and 21 in the half-roll machine shown in FIGS . 1 and 2 and also the housing inner walls of the quarter-roll machines in the same way as the metallic surfaces of the pistons run on foam to pair the foam with roughened material, in particular, the flanks of the pistons can be ground in this way.

In Figs. 4 and 5 embodiments are shown by fiction, according foamed piston of a half or quarter roller blower in which bodies into the foam 70 in Fig. 4 and 71 in Fig. 3 cavities 72 and 73 by axially parallel in the Ausschäumwerkzeug a set mold cores are formed. These mold cores can after curing the foam, for. B. the polyurethane foam can be pulled out axially.

Fig. 6 shows a conventional Roots blower, in which the on the housing raceways 74 , 75 and on the con cave surfaces of the counter-piston convex surfaces 76 of the pistons 77 and 78 are formed by foam bodies 79 . This foam body can all be anchored to the aluminum piston according to the above described the half and quarter roll blower with ribs. Here, too, a foam surface always runs onto metal surfaces, which must be roughened in the manner described above.

In Fig. 7 is a meshing rotating piston blower is shown, which is formed by a piston corresponding to the piston of the above-described Roots blower 80 and a three blocking parts 81 having counter-rotor 82 which rotate in a cylindrical housing 83 . The piston 80 runs against the inner surfaces of the shut-off parts 81 , which are lined with foam according to the invention on the contact surfaces 84 . The shut-off parts 81 in turn run with foam-lined cylinder surfaces 85 on the housing raceway 86 . Here it is shown that the foam body, which form the surfaces 84, are pressed by the centrifugal forces on the shut-off parts 83 carrying them. Therefore, only the foam body that forms the surfaces 85 require a special anchoring. However, it is also possible to coat the housing race 86 instead of the cylindrical surfaces 85 of the shut-off parts 81 with foam, in order to take advantage of the centrifugal force effect here as well, which, however, requires a larger design effort.

In Fig. 8, a conventional screw compressor is provided, in which the contact surface 90 of the right screw in the drawing and the flanks 91 and 92 of the threads of the counter screw 93 are lined with foamed plastic, so that they always start on roughened metal.

In FIGS. 9 and 10, a known scroll compressor is illustrated, in which the housing 100, the fixed in this spiral wall 101 and the rotor are indicated by 102. The rotor 102 carries on its radially inner wall, which starts at the spiral wall 101 of the housing 100 , a coating 103 made of foamed plastic, while the counter surface 104 of the wall 101 consists of roughened metal. In this way, care is taken that the foam coating is arranged on the centrifugal force side, that is, the centrifugal force is always pressed against the wall carrying it, so that no special anchoring is required. Here, too, the foam always runs against roughened metal.

• Reference numeral list: Figures 1 and 2 1 wings.
  2 large radius cylinder surfaces
  3 cylinder surface with small radius
  4, 5 engagement surfaces
  6, 7 convex curves
  8 outer flat engagement surface
  9 inner flat engagement surface
  10, 11 concave curves
  12 parting plane
  13 plastic body
  14 drive pins
  15 light metal profile
  16 piston part with small radius
  17 counterweight
  18, 19 shaft journals
  20, 21 housing side walls
  22, 23 disks
  24, 25 screw connections
  26, 27, 28, 29, 30 ribs of 15
  31, 32, 33 Anchoring the ribs
  34 Breakthrough of the ribs
  35 opening in rounding 6 or 7
  36 recesses in 22, 23
  37 recesses on the wing side
  38 recesses on page of 16
  39 counter contact surfaces to 37 and 38
  40 edges of the shaft bearing rings Fig. 3
  41, 42 wings
  43 foam body
  44, 45, 46, 47, 48, 49 ribs
  50 light metal profile
  51 wave
  52 anchorages
  53 breakthroughs
  54 cylinder surface with large radius
  55 cylinder surface with small radius
  56 convex rounding made of metal
  57 convex rounding made of foam for Fig. 1 58, 59 shell raceway
  60 piston flanks Fig. 4 and 5 70, 71 foam body
  72, 73 cavities Fig. 6 74, 75 housing raceways
  76 convex contact surfaces
  77, 78 pistons
  79 foam body Fig. 7 80 pistons
  81 shut-off parts
  82 counter-rotating
  83 housing
  84 contact surfaces of the shut-off parts 81
  85 cylinder surfaces of the shut-off parts 81
  86 Housing race Fig. 8 90 Contact surface of one screw
  91, 92 flanks of the threads of the counter screw 93
  93 counter screw Fig. 9 and 10 100 housing
  101 fixed spiral wall
  102 rotor
  103 coating
  104 counter surface

Claims (8)

1. Rotary piston blower with against each other at rela tive speed contact-free, between a gap seal forming working or shut-off parts and work space walls, characterized in that one of each of the starting parts ( 16, 39, 41, 42, 55, 58, 59 , 70, 71, 74, 75, 77, 78, 80, 81, 86, 90, 93, 100, 102 ) on its approaching surfaces ( 2 , 7 , 54 , 57 , 76 , 84 , 85 , 90 , 91 , 92 , 103 ) is made of foamed plastic and that the counter surfaces ( 3 , 6 , 39 , 55 , 56 ) tarnished by these surfaces ( 2 , 7 , 54 , 57 , 76 , 84 , 85 , 90 , 91 , 92 , 103 ) , 74 , 75 , 80 , 86 , 93 , 104 ) of the other part ( 16 , 39 , 55 , 58 , 59 , 74 , 75 , 80 , 86 , 93 , 100 ) consist of roughened metal. 2. Rotary piston blower according to claim 1, characterized in that it is a known external-axis rotary piston blower of half or quarter construction with a housing consisting of side walls and two overlapping cylinder jacket surfaces, which is axially penetrated by the piston shafts and in the overlap zones of the cylinder surfaces have inlets and outlets in which the pistons have at least one wing ( 1 , 41 , 42 ) with a cylinder surface ( 54 ) with a large radius on their outer raceways and on a cylinder surface ( 3 , 55 ) small radius and convex roundings ( 6 , 7 , 56 , 57 ) of the engagement surfaces ( 8 , 9 ) of the respective other piston lying between the cylinder surfaces ( 3 , 54 , 55 ) start or roll off without contact, the wings ( 1 , 41 , 42 ) the piston from a with radial ribs ( 26 , 27 , 28 , 29 , 30 , 44 , 45 , 46 , 47 , 48 , 49 ) with anchors ( 31 , 32 , 33 , 52 ) Send sections of a light metal profile ( 15 , 50 ) and in this Leichtmetallpro fil ( 15 , 50 ) in a the outer shape of the contact surfaces ( 2 , 7 , 54 , 57 ) made of foamed plastic of the wing ( 1 , 41 , 42 ) reproducing die casting tool foamed bodies ( 13 , 43 ) exist. 3. Rotary piston blower according to claim 1, 2 characterized in that the engagement surfaces ( 8 , 9 ) of the light metal profile ( 15 , 50 ) are formed and that the convex roundings ( 7 , 57 ) are formed on one side of the wing by foamed plastic. 4. Rotary piston blower according to claim 1, 2, 3 characterized in that in rotations in the side walls ( 20 , 21 ) of the housing around the shaft journal ( 18 , 19 , 51 ) arranged disks ( 22 , 23 ), in which concentric recesses ( 36 , 37 , 38 ) are angeord net, in which inserts made of foamed plastic are provided which start on the mating surfaces ( 39 , 40 ) of the recesses in the side walls ( 20 , 21 ). 5. Rotary piston blower according to claim 4, characterized in that in half-roller blowers, the recesses ( 37 ) on the side of the wing ( 1 ) have a smaller axial depth than the Ausneh lines ( 38 ) on the side of the piston part ( 16 ) with a small radius. 6. Rotary piston blower according to claim 1, characterized in that with arrangement known per se uniform pistons ( 77 , 78 ), the two wings with convex thrust faces ( 76 ) and between these concave thrust faces, the convex thrust faces ( 76 ) of Foam bodies are formed. 7. Rotary piston blower according to claim 1, characterized in that the arrangement of known helical pistons, the outer tooth-shaped spiral contact surface ( 90 ) of a piston and the flanks ( 91 , 92 ) of the thread of the counter-piston ( 93 ) are formed by foam bodies. 8. Rotary piston blower according to claim 1; characterized in that the contact surfaces negatively loaded by centrifugal force are formed by foam bodies ( 84 , 85 , 103 ).